Seat assembly with inner seat back movable with a seat cushion

ABSTRACT

A seat assembly includes a seat cushion and a seat back. The seat cushion has opposite front and rear ends. The seat cushion is selectively height adjustable relative to the floor of the vehicle. The seat back has nested outer and inner support members. The outer support member has an upper portion extending between spaced apart side bolsters. The inner support member is disposed between the side bolsters and below the upper portion of the outer support member. The inner support member is operatively coupled to the seat cushion for movement therewith relative to the outer support member. The inner support member remains below the upper portion of the outer support member to provide continuous support to the lower portion of the occupant&#39;s back during adjustment of the seat cushion relative to the floor of the vehicle.

RELATED APPLICATIONS

This application is a continuation-in-part of U.S. Non-provisionalapplication Ser. No. 11/136,061, filed May 24, 2005, which applicationclaims priority of U.S. Provisional Patent Application 60/574,030, filedMay 24, 2004.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to seat assemblies for motor vehicles. Moreparticularly, the invention relates to a seat back having an inner seatback independently movable with respect to an outer seat back.

2. Description of the Related Art

A motor vehicle includes at least one seat assembly for supporting anoccupant within a passenger compartment of the motor vehicle. The seatassembly includes a seat cushion and a seat back for supporting thetorso of an occupant seated on the seat cushion. Typically, the seatback is pivotable relative to the seat cushion between a plurality ofseating positions. Further, the seat assembly is typically mounted to afloor mounted seat adjuster that allows horizontal and vertical comfortadjustment of the seat cushion and seat back together relative to thefloor of the vehicle.

Some seat assembly designs, commonly referred to as “All Belt to Seat”(ABTS) designs, include belt restraint devices incorporated into theseat structure. Vehicle manufacturers desire ABTS designs for a varietyof reasons, such as reduced complexity in the assembly of the vehicle,improved comfort due to the more proximal location of the belt exitpoint relative to the occupant, and packaging concerns related to aparticular vehicle design.

The seat back in a conventional ABTS design typically includes at leastone reinforced side member that bears the majority of the forces or“belt loads” associated with the restraint device. Due to the potentialmagnitude of the belt loads, the reinforced side member is coupleddirectly to the horizontal rails of the seat adjuster. As a result, theseat back in a conventional ABTS design is not vertically adjustablewith the seat cushion.

It, therefore, remains desirable to provide an ABTS design having a seatback, or at least a portion thereof, movable with the seat cushion toprovide proper back support of the occupant through the adjustment rangeof the seat cushion.

SUMMARY OF THE INVENTION

According to one aspect of the invention, a seat assembly is providedfor supporting an occupant above a floor of a motor vehicle. The seatassembly includes a seat cushion, an adjuster assembly and a seat back.The seat cushion has opposite front and rear ends. The adjustermechanism is operatively coupled between the floor of the motor vehicleand the seat cushion. The adjuster mechanism allows selective horizontaland vertical adjustment of the seat cushion relative to the floor. Theseat back assembly includes an outer frame, an inner frame, an outerfoam pad and an inner foam pad. The inner frame has an upper endslidably and pivotally coupled to the outer frame. The inner frame has alower end pivotally coupled to the seat cushion. The outer foam pad isfixedly secured to the outer frame. The outer foam pad has an upperportion extending between spaced apart side bolsters. The inner foam padis disposed between the side bolsters and below the upper portion of theouter foam pad. The inner foam pad is fixedly secured to the inner framefor vertical and pivotal movement relative to the outer foam pad inresponse to corresponding vertical and pivotal movement of the seatcushion relative to the floor.

According to another aspect of the invention, the seat assembly includesa seat cushion and a seat back. The seat cushion has opposite front andrear ends. The seat cushion is selectively height adjustable relative tothe floor of the vehicle. The seat back has nested outer and innersupport members. The outer support member has an upper portion extendingbetween spaced apart side bolsters. The inner support member is disposedbetween the side bolsters and below the upper portion of the outersupport member. The inner support member is operatively coupled to theseat cushion for movement therewith relative to the outer supportmember. The inner support member remains below the upper portion of theouter support member to provide continuous support to the lower portionof the occupant's back during adjustment of the seat cushion relative tothe floor of the vehicle.

BRIEF DESCRIPTION OF THE DRAWINGS

Advantages of the present invention will be readily appreciated as thesame becomes better understood by reference to the following detaileddescription when considered in connection with the accompanyingdrawings, wherein:

FIG. 1 is a front perspective view of a seat assembly according to anembodiment of the invention;

FIG. 2 is a perspective view of an adjuster assembly for the seatassembly;

FIGS. 3-8 are perspective views of the seat assembly of FIG. 1illustrating the various positions of the seat cushion and seat back ofthe seat assembly;

FIGS. 9 and 10 are front perspective views of another embodiment of theinvention with the seat cushion and inner support member shown invertically lowered and elevated positions, respectively; and

FIGS. 10 and 11 are front perspective views of a frame structure formoving the seat cushion and inner support member together relative tothe outer support member of the seat back.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, a seat assembly for a motor vehicle is generallyindicated at 10. The seat assembly 10 includes a generally horizontalseat cushion 12, a generally upright seat back 14, and a head restraint16 fixedly secured to a top portion of the seat back 14. The seatassembly 10 also includes an adjuster mechanism 20 coupled between abottom surface of the seat cushion 12 and the floor of the vehicleallowing selective vertical adjustment of the seat cushion 12 relativeto the floor. Described in greater detail below, the seat back 14includes an inner frame coupled to the seat cushion 12 for movementtherewith to provide optimal support of the occupants back duringadjustment of the seat cushion 12 relative to the floor of the vehicle.

Referring to FIG. 2, the adjuster mechanism 20 includes opposite andspaced apart inboard 21 and outboard 22 sides. Each side of the adjustermechanism 20 includes a lower track 24 and an upper track 26. The lowertrack 24 is fixedly secured to the floor of the vehicle. The upper track26 is slidably coupled to the lower track 24 for generally forward andrearward movement of the upper track 26 relative to the floor of thevehicle. A bottom support frame 36 for supporting the seat cushion 12 isoperatively coupled to the upper track 26 for vertical movement of thebottom support frame 36 and seat cushion 12 relative to the upper track26. A first support member 30 and a second support member 32 are mountedto the upper track 26 on the outboard side 22. A load transfer member orbeam 34 is fixedly secured to the first 30 and second 32 supportmembers.

Preferably, the horizontal movement of the upper track 26 relative tothe lower track 24 and the vertical movement of the bottom support frame36 relative to the upper track 26 are driven by electric motors, whichare generally indicated at 40. A more detailed description of theadjuster mechanism 20 and its operation are disclosed in U.S. Pat. No.6,089,665, the content of which is incorporated herein by reference inits entirety.

Referring back to FIG. 1, the seat back 14 includes an outer frame 50and an inner frame 60. The outer frame 50 has generally parallel andspaced apart side members 52 each extending between opposite upper andlower ends. The outer frame also has a cross member 56 that extendsbetween the upper ends of the side members 52. The lower ends of theside members 52 are fixedly secured to respective upper tracks 26 byrecliner mechanisms 58 providing pivotal movement of the seat back 14relative to the upper track 26 about a recline axis 28. Preferably, therecliner mechanisms 58 are continuously engaged rotary recliners, asknown by those of ordinary skill in the art. Most preferably, therecliner mechanisms 58 are driven by electric motors (not shown). Theinner frame 60 is adapted to fit in the space defined between the sidemembers 52. The inner frame 60 has sides 62 generally parallel with theside members 52 of the outer frame 50.

Each frame 50, 60 is covered by a foam pad concealed by a cut and sewntrim cover. The foam pads are shaped to substantially follow the shapeof the respective underlying frames 50, 60. Generally, the foam padsprovide an occupant supporting surface for each frame 50, 60.Preferably, bolsters 54 for supporting the sides of the occupant's torsoare defined in the foam pad extending along the side members 52; and alumbar support 64 is defined in the foam pad covering the inner frame60.

Slots or grooves 70 are formed in the side members 52. Optionally,tracks having grooves are fixedly secured to the side member 52. Thegrooves 70 define a path of movement for the inner frame 60. The pathcan be linear, arcuate, or a combination thereof. Preferably, the pathis substantially parallel with the side members 52. The inner frame 60is slidably coupled to the side members 52 of the outer frame 50 formovement along the path. More specifically, pins 72 extend outwardlyfrom the sides 62 of the inner frame 60, which are slidably engaged withthe respective grooves 70 of the side members 52. A bottom edge 74 ofthe inner frame 60 is pivotally coupled to a rear end of the seatcushion 12 for movement about a pivot axis 76. Vertical adjustment ofthe seat cushion 12 causes corresponding sliding movement of the innerframe 60 relative to the outer frame 50 along the path defined by thegrooves 54. By this arrangement, the lumbar support 64 on the innerframe 60 can remain in close proximity to the lumbar region of theoccupant as the seat cushion 12 is vertically and/or horizontallyadjusted. The pivot axis 76 defined between the inner frame 60 and theseat cushion 12 is generally parallel with and spaced apart from therecline axis 28 of the outer frame 50. The pins 72, therefore, allow theinner frame 60 to slide and pivot relative to the outer frame 50 duringpivotal movement of the outer frame 50 about the recline axis 28 toaccommodate the spaced relation between the recline axis 28 of the outerframe 50 and the pivot axis 76 between the inner frame 60 and the seatcushion 12.

Optionally, longitudinally extending flanges along the sides 62 of theinner frame 60 are slidably engaged with the grooves 70 instead of thepins 72, so that movement of the inner frame 60 is limited to slidingmovement along the path defined by the grooves 70. In this case, thepivotal connection between the bottom edge 74 of the inner frame 60 caninclude a lost motion arrangement, such as a pin and slot design, toaccommodate the spaced relation between the recline axis 28 of the outerframe 50 and the pivot axis 76 between the inner frame 60 and the seatcushion 12 during movement of the outer frame 50 about the recline axis28. Alternatively, rearward reclining adjustment of the outer frame 50can be limited by design, thereby obviating the need to address thespaced relation between the recline axis 28 of the outer frame 50 andthe pivot axis 76 between the inner frame 60 and the seat cushion 12.

Optionally, the top portion of inner frame 60 can be fixedly secured tothe top portion of outer frame 50, while the bottom part of frame 60 isallowed to flex or stretch and remain connected with seat cushion 12during rotation of the outer frame 50 about the recline axis 28.

In another embodiment of the invention, the head restraint 16 is fixedlysecured to the top portion of the inner frame 60 for sliding movementtherewith relative to the outer frame 50. Alternatively, the headrestraint 16 can be mounted to a top portion of the outer frame 50 and,therefore, not move with the inner frame 60 during vertical adjustmentof the seat cushion 12.

In use, the occupant can adjust the seat cushion 12 between a downposition, as shown in FIG. 4, an up position, as shown in FIG. 6, andany one of a plurality of vertical positions therebetween, asillustrated by the middle position shown in FIG. 5. The seat back 14will follow vertically with the rear end of the seat cushion 12 amongthese aforementioned vertical positions. The seat back 14 also followsthe vertical displacement of the rear end of the seat cushion 12 as theseat cushion 12 is tilted between the base position of FIG. 7 and thetilted position of FIG. 8.

In another embodiment of the invention, the seat assembly 10 is an ABTSseat incorporating the aforementioned outer 50 and inner 60 frameconstruction. At least one of the side members 52 of the outer frame 50,i.e. the side member 52 that is outboard with respect to the vehicle,comprises a tower member 80 adapted to withstand torsional and bendingforces or loads associated with the weight of the occupant against aseat belt 81 during a sudden deceleration of the vehicle. The beltretractor 82 is fixedly secured to any suitable location on the seatassembly 10, such as within the tower member 80 or to a bracketdepending from the outer frame 50 of the seat back 14. The belt isguided by a spool through an opening or belt exit 84 defined along afront face of the tower 80. The free end of the belt is fixedly securedto the upper track 26, on the same side of the seat assembly as thetower 80. Optionally, the belt exit 84 is defined in a bezel (not shown)that is movably adjustable in a longitudinal sense along the tower 80.

In FIGS. 9-10, a second embodiment of the seat assembly is shown,wherein like elements are indicated by numerals offset by 100. In thisembodiment, the seat back 114 has an outer support member or foam padthat has a generally inverted U-shape defined by an upper portion 53 andspaced apart bolsters 154 extending downwardly from opposite sides ofthe upper portion 53. An inner support member or foam pad 164 isdisposed between the bolsters 154 and below the upper portion 53. Thehead restraint 116 is supported along a top surface of the upper portion53.

Referring now to FIGS. 11-12, the outer foam pad is supported by theouter frame 150. The inner foam pad 164 is supported by the inner frame160. The inner frame 160 is slidably coupled to the side members 152 ofthe outer frame 150. More specifically, a pair of tracks 90 is fixedlysecured to respective side members 152 of the outer frame 150. Eachtrack 90 has a generally U-shaped cross section defined by a main wall92 and spaced apart side walls 94 extending substantially orthogonallyfrom opposite sides of the main wall 92. A pair of sliding members orrollers 95 is fixedly secured to opposite sides of the inner frame 160.The sliding members 95 are engaged with respective tracks 90 on the sidemembers 152 to allow both sliding and pivotal movement of the innerframe 160 relative to the outer frame 150.

The bottom end of the inner frame 160 is pivotally coupled to the seatcushion 112 by a pivot pin 172. The pivotal connection between the innerframe 160 and the seat cushion 112 allows the inner frame 160 and theinner foam pad 164 to move with the seat cushion 12 as it is adjusted invertical and/or horizontal directions. Thus, the inner foam pad 164provides proper support of the occupant's lumbar region in any of thevertical and horizontal positions of the seat cushion 12.

The inner frame 160 includes generally parallel and spaced apart sides.A suspension 180 extends between the sides of the inner frame 160. Itshould be appreciated that any suitable suspension known by thoseskilled in the art can be supported by the sides of the inner frame 160,such as an adjustable lumbar support mechanism. Additionally, thesuspension 180 can be oriented in a generally vertical manner betweenthe opposite top and bottom ends of the inner frame 160 rather than thehorizontal manner shown in FIGS. 11 and 12.

The invention has been described in an illustrative manner. It is,therefore, to be understood that the terminology used is intended to bein the nature of words of description rather than of limitation. Manymodifications and variations of the invention are possible in light ofthe above teachings. For example, the sides of the inner frame 160 areshown as straight. Those skilled in the art should, however, readilyappreciate that the sides of the inner frame 160 can have any shapenecessary to achieve a desired level of support while remaining withinthe packaging constraints of the particular outer seat design. Thus,within the scope of the appended claims, the invention may be practicedother than as specifically described.

1. A seat assembly for supporting an occupant above a floor of a motorvehicle, the seat assembly comprising: a seat cushion having oppositefront and rear ends; an adjuster mechanism operatively coupled betweenthe floor of the motor vehicle and the seat cushion, the adjustermechanism allowing selective horizontal and vertical adjustment of theseat cushion relative to the floor; and a seat back assembly having: anouter frame; an inner frame having an upper end slidably and pivotallycoupled to the outer frame, the inner frame having a lower end pivotallycoupled to the rear end of the seat cushion; an outer foam pad fixedlysecured to the outer frame, the outer foam pad having an upper portionextending between spaced apart side bolsters; an inner foam pad disposedbetween the side bolsters and below the upper portion of the outer foampad, the inner foam pad being fixedly secured to the inner frame forvertical and pivotal movement relative to the outer foam pad in responseto corresponding vertical and pivotal movement of the seat cushionrelative to the floor.
 2. The seat assembly as set forth in claim 1,wherein the outer frame includes a pair of side members that aregenerally parallel and spaced apart, at least one of the side membershaving a track fixedly secured thereto and slidably engaged with theinner frame.
 3. The seat assembly as set forth in claim 2 including asuspension extending between generally parallel and spaced apart sidesof the inner frame for movement therewith relative to the outer frame.4. The seat assembly as set forth in claim 3, wherein both sides of theinner frame are pivotally coupled to the seat cushion by a pivot rod. 5.The seat assembly as set forth in claim 1 including a head restraintslidably coupled to the outer frame for selective height adjustmentrelative to the upper portion of the outer foam pad.
 6. A seat assemblyfor supporting an occupant above a floor of a motor vehicle, the seatassembly comprising: a seat cushion having opposite front and rear ends,the seat cushion being selectively height adjustable relative to thefloor of the vehicle; a seat back with nested outer and inner supportmembers, the outer support member having an upper portion extendingbetween spaced apart side bolsters, the inner support member beingdisposed between the side bolsters and below the upper portion of theouter support member, the inner support member being operatively coupledto the seat cushion for movement therewith relative to the outer supportmember, the inner support member remaining below the upper portion ofthe outer support member to provide continuous support to the lowerportion of the occupant's back during height adjustment of the seatcushion relative to the floor of the vehicle.
 7. The seat assembly asset forth in claim 6, wherein a lower end of the inner support member ispivotally coupled to the seat cushion.
 8. The seat assembly as set forthin claim 7, wherein the seat cushion is independently horizontallyadjustable relative to the outer support member of the seat back.
 9. Theseat assembly as set forth in claim 8, wherein an upper end of the innersupport member is slidably and pivotally coupled to the outer supportmember accommodating movement of the inner support member together withthe seat cushion during height and horizontal adjustment of the seatcushion relative to the outer support member.
 10. The seat assembly asset forth in claim 6 including a head restraint supported by the outersupport member of the seat back.